In ventilation duct systems, there are oftentimes a variety of components connected to the duct system that must be periodically inspected, maintained, and repaired. Due to their internal construction, however, these components are typically not easily accessible for routine inspection, maintenance, and repair.
Internal components include those that condition the flow of fluid within the ductwork. These devices may include inline fans, manual or automatic dampers, or venturi air devices to name only a few. Normally these types of devices are assembled within a housing or enclosure and are inserted into the duct system so that the duct slides over a section of the housing. To prevent ingress of exterior gasses or egress of the fluid from the duct, a sealer may be used at each joint between the ductwork and the device housing. Typically, the sealer is in fluid-like form and is distributed between a surface of the duct and a surface of the device. Once the sealer is distributed, it may cure to a solid-like, pliable form to provide a fluid-tight seal.
This type of installation makes removal of the device from the ductwork difficult or impossible without significant expenditure of effort to disassemble each joint to free the device from the ductwork. Furthermore, this type of disassembly may result in damage to the adjacent ductwork and/or damage to the device itself thus necessitating repair of the duct and/or replacement of the device. Oftentimes, as a result, inspection, maintenance, and repair operations become costly endeavors because of the effort required and potential damage associated with the removal of the device.
Attempts to address the costs associated with removal of these devices for inspection, maintenance, and repair operations have been generally unsuccessful. In this regard, the devices have been made available with a flanged housing or enclosure. The premise is that a flanged enclosure, when bolted to a mating flange on adjacent ductwork, may be more easily disassembled by unbolting the flanges and removing the device from between adjacent ductwork. Generally, the flanges used are separate annular rings of metal that are typically welded to the housing at each end. The weld seam is therefore between the annular ring and the housing and is generally externally positioned to be between the adjacent ductwork and the device. As such, the weld seam is typically exposed to the fluid flow through the ductwork.
However, a weld seam at this location is possibly problematic, particularly where air quality is paramount. For example, food processing facilities are acutely sensitive to the presence of bacteria in the facility and spare no expense to eradicate sources of potential repositories of bacteria. Because the ductwork is critical to cleanliness of the facility, weld joints in the ductwork are disfavored. More specifically, a weld seam by which a flange is attached to a device enclosure is exposed to the fluid flow within the ductwork. And, because of the generally rough nature of a raw or unfinished weld joint, the weld may harbor bacteria and, at the same time, resist cleaning efforts to keep the ductwork bacteria free. Furthermore, a weld is more likely to corrode, which may be another source of contamination for the fluid inside the ductwork. Thus, welding the flange to the device simply to allow ease of inspection, maintenance, or repair, is disfavored by industries that require high quality, substantially contaminant-free air.
Thus, there is a need for improved access to components internal to the ductwork, that overcomes these and other shortcomings and drawbacks of known components in ventilation duct systems.